Electron discharge device



Jan. 18, 1949. P. 1.. SPENCER ELECTRON DI S CHARGE DEVI CE Filed March 3, 1945 .5 T ima .MQ J 5E.

F m w Patented Jan. 18, 1949 ELECTRON DISCHARGE DEVICE Percy L; Spencer, West Newton, Mass, assignor to Raytheon Manufacturing Company, Newton,

Mass.,'a corporation of Delaware 'Application'March 3, 1945, Serial No. 580,767

My present invention relates to electron-discharge devices, and'morepar-ticularlyto electron-discharge devices of the so-called magnetron type.

Devices of this character generally incorporate means for-establishing a magnetic field in a direction normal tothe dischargepath therein, and it is often necessary, foreXample, when operating at high power levels, that this field be quite intense.

Heavy, bulky magnets or field coils have heretofore been employed for this purpose; but in applications where space and Weight are at a premium, this is not satisfactory.

It is, therefore, themain object of my present invention to improve them sans heretoforeemployed for establishing such magnetic fields,-by so constructing the same that the size and weight thereof may be considerably reduced, without, however, diminishing the intensity of the field created thereby.

It is another object of my pesent invention to provide a magnet pole piece, particularly, but not necessarily, for electron-discharge devices of the magnetron type, which can readily be shaped to conform to the circumstances under which it is to be used.

In the accompanying specification I shall describe, and in the annexed drawing show, an illustrative embodiment of the devices of my present invention. It is, however, to be clearly understood that I do not wish to be limited to the details herein shown and described for purposes of illustration only, inasmuch as changes therein may be made without the exercise of invention and within the true spirit and scope of the claims hereto appended.

In said drawing, Fig. 1 is a transverse sectional view taken substantially through the center of an electron-discharge device assembled in accordance with the principles of my present invention;

Fig. 2 is an end view of a magnet pole piece constituting a component of the device shown in Fig. 1; and

Fig. 3 is a side elevational View of the same.

Referring now more in detail to the aforesaid illustrative embodiment of my present invention, and with particular reference to the drawing, the numeral 5 generally designates an edectron-discharge device of the magnetron type. Said device includes an open-ended cylindrical body *8 made of highly conductive material, such as copper, and said body is provided with a plurality of radially disposed anode members 1 extending interiorly from the inner Wall thereof.

An indirectly heated cathode 8, which may be of the oxide-coated type, is adapted to be supported coaxially in said body 6 whereby an annular discharge space 9 is presented between the '2 Claims. (Cl. 250-27.5)

--sealed thereto. .29 are'provided wlth'central openingsll and 22 2 same and the inner edges of the anode members 1, which inner edges constituteelectron-receivingfaces-IU.

"By way of example, the cathode B'may be supported by filamentwires H and I2 which,*in turn, maybe supported by lead-in conductors'l3 and M. The latter enter-the'body 6 through pipes 15 and l Shermetically sealed in'said body, said pipes being provided at their outer ends with glass seals I? and 18 in which the lead-in conductors -l3:and l tmay be embedded.

The-open endsof the body "6 are closed by-end plates I 9 ancl 2B,-like said bodyymade of-highly conductive material, and being hermetically Preferably, the end plates 1 Band through which extend,in axial alignment with the cathode 8, pole pieces generallydesignated 'by the reference characters 23- and 24.

Each such pole piece comprises a hollow mem- .b'eror shel1 25 madeof conductive material, such as sheet steel, copper, or the like, which should be sufliciently thin and malleable to permit its being shaped to conform to the physical surroundings in Which it is to be used. For example, in the embodiment under consideration, the shell member 25 is seen to include a cylindrical inner portion 26 having a front wall 21 provided with a recess 28 to enable the accommodation of a portion of the supporting means of the cathode 8. It is this cylindrical portion 26 which extends into the body 6 through the openings 2|, 22 of the end plates I9, 20. The diameter of said inner portion 26 may be increased, as at 29, to present an intermediate cylindrical portion 30, which abuts the outer surface of each of the end plates l9 and 20 and is hermetically sealed thereto. At 3|, the shape of the shell member is, preferably, transformed from cylindrical to rectangular cross-section, thereby providing an outer rectangular portion 32 having flat surfaces. The outer end of said rectangular portion 32 may be closed by a cover plate 33.

It is to be clearly understood that the specific shape of the pole pieces herein shown and described is by way of illustration only, it being intended, in accordance with the principles of my present invention, that these members be shaped to suit the requirements of the use to which they are going to be put. In the electron-discharge device disclosed herein, the specific shape above described appears to be appropriate. It is to be further understood that while the pole pieces are shown to extend into the body 6 through end plates [9 and 20, in some cases, said end plates can be eliminated and the pole pieces themselves can serve to close the ends of the body 6.

The shell member 25 is filled with a finely divided magnetic material 34, such as Alnico, or any other comminuted magnetic material of high co- 3 ercive force, such material being firmly compacted into the shell, and preferably sintered, and heattreated by methods well known in the art to obtain maximum magnetic properties, prior to closing said shell with the cover plate 33.

While other magnetic means may be employed for the purpose, I prefer to aifix to one of the flat surfaces of the outer rectangular portion 32 of the shell 25 of each pole piece the ends of a horseshoe magnet 35. Said magnet 35 may be secured to the body 6 of the device by means of a bolt 36, passing through an opening 31 in said magnet, and anchored in said body 6, the entire assembly being firmly held by a lock-nut 38 bearing against the outer surface of said body 6.

This completes the description of the aforesaid illustrative embodiment of my present invention. It will be noted from all of the foregoing that I have provided a simple structure for applying a magnetic field, for example, to an electron-discharge device of the magnetron type, which is of reduced Weight and whose design makes maximum use of space. It will also be noted that the pole pieces incorporated in such structure readily lend themselves to a wide variety of shapes, thereby enabling the positioning thereof in such manner as to obtain maximum intensity of the magnetic field therebetween.

Other objects and advantages of my present invention will readily occur to those skilled in the art to which the same relates.

What is claimed is:

1. An electron-discharge device comprising an envelope provided with interiorly extending anode members; a cathode supported in said envelope 4 in spaced relationship with respect to said anode members; magnet pole pieces extending into said envelope in axial alignment with said cathode; each of said pole pieces consisting of an electrically conductive, readily malleable, thin-walled shell having compacted therein finely divided magnetic material, and a magnet secured to and connecting said pole pieces exteriorly of said envelope.

2. An electron-discharge device comprising a hollow cylindrical body provided with interiorly extending anode members; a cathode supported coaxially within said body; end plates secured to said body; magnet pole pieces extending into said body through said end plates in axial alignment with said cathode; each of said pole pieces consisting of an electrically conductive, readily mal- I leable, thin-walled shell having compacted therein; finely divided magnetic material; and a magnet; secured to and connecting said pole pieces exteriorly of said body.

PERCY L. SPENCER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,062,938 Ruppe Dec. 1, 1936 2,275,880 Arey Mar. 10, 1942 2,295,396 George Sept. 8, 1942 2,305,781 Helbig Dec. 22, 1942 2,307,205 Ewald et a1 Jan. 5, 1943 2,328,222 McCarthy Aug. 31, 1943 2,348,986 Linder May 16, 1944 2,416,899 Brown Mar. 4, 1947 

